Unit Well 26

Residual Chlorine Level

At 9:10 PM on Tuesday, January 22, 2008 the Madison Water Utility determined that the residual chlorine level at Unit Well 26 dropped below the Utility's established minimum level of 0.15 mg/L to 0.14 mg/L. Per the Utility's standard operating procedure the Waterworks Operator contacted the Water Supply Manager and staff were dispatched to the site to shut down the booster pumps. All customers served by this well can be assured that the water entering the distribution system was safe for consumption. The calculated concentration time (CT) value for Unit Well 26 based on its lowest residual chlorine level was over 80 times more than the minimum required CT value for the 4-log removal of viruses. We are providing this information per our adopted External Communications Plan to let our customers know that while problems will inevitably occur within our system, we have adopted the necessary procedures to respond to them appropriately and ensure the delivery of a safe product.